The detection of antigenic determinants of Acinetobacter baumannii

Immunol Lett. 2017 Jun:186:59-67. doi: 10.1016/j.imlet.2017.04.004. Epub 2017 Apr 18.

Abstract

Background: Acinetobacter baumannii continues to pose a threat to burdened patients in ICUs all around the world. Lately, infection control techniques are not sufficient to curb A. baumannii's progression and chemotherapeutics are losing their potency against it. Thus, immunization became a key player in providing an ideal solution to the dilemma. None of the vaccines under investigation have reached the market and the search for a tailored vaccine remains a challenge. The notion of unravelling the bacterial antigens to design a novel epitope-based vaccine proved its merits.

Methods: In this work, the propitious polysaccharide and protein antigenic determinants of A. baumannii were mapped by mimicking the infection. The immune response was evaluated by western blot, ELISA, and cellular proliferation assay techniques.

Results: The screening showed that OMPs induced the most eminent sustained IgG response. In addition, OMP gave the highest cellular proliferation and a fold increase in ELISA that reached up to 10-fold by week 6. Whilst, the LPS gave a rapid IgM response, that reached 5-fold and the response was visible from week 1 in the western blot. The OMPs had a more pronounced effect in eliciting a cellular immune response.

Conclusion: The results elaborated the valuable role of using pure OMPs and detoxified LPS together; as a major cornerstone in designing an ideal vaccine against A. baumannii.

Keywords: Acinetobacter baumannii; Epitope mapping; Lipopolysaccharide; Outer membrane protein; Vaccines.

MeSH terms

  • Acinetobacter Infections / immunology*
  • Acinetobacter baumannii / immunology*
  • Animals
  • Antigens, Bacterial / immunology
  • Antigens, Bacterial / metabolism*
  • Bacterial Vaccines / immunology*
  • Cell Proliferation
  • Cells, Cultured
  • Critical Care
  • Cross Infection / immunology*
  • Epitope Mapping
  • Epitopes / immunology
  • Epitopes / metabolism*
  • Humans
  • Immunity, Humoral
  • Immunization
  • Immunoglobulin G / blood
  • Mice
  • Mice, Inbred C57BL
  • Orotidine-5'-Phosphate Decarboxylase / immunology
  • Orotidine-5'-Phosphate Decarboxylase / metabolism*

Substances

  • Antigens, Bacterial
  • Bacterial Vaccines
  • Epitopes
  • Immunoglobulin G
  • Orotidine-5'-Phosphate Decarboxylase